"Properties of soil in Chiba University's Atagawa Farm [Shizuoka, Japan], 3: Mineralogical properties and soil classification of volcanic ash soils."

"Analysis of mineralogical properties by X-ray fluorescence spectrometry and X-ray diffraction combined with selective dissolution were performed on soil samples collected from soil horizons in Site 4 (located on lower part of the gentle foot slope in Chiba University's Atagawa farm). Total element analysis and identification of clay mineral composition of soils in Site 1 (located on top of hill in the farm) were also carried out for comparison with the properties of Site 4. The soil of Site 4 contained about 15% of allophane, and showed the high content of humus in surface layers and high values of phosphate absorption coefficient over 15 in all horizons. The soil of Site 4 was classified into Typic Kuroboku soil because of filling the classification criteria of Kuroboku soils according to the Unified Soil Classification System of Japan (1st Approximation) by Pedologist. In addition, the soil in Site 4 having Andic soil property was classified into Typic Melanudants by Soil Taxonomy. The soil in Site 1 showing low sensitivity of active alumina test, low phosphate absorption coefficients, brownish soil colors, and a poor character of Kuroboku A horizons and poor character of allophanic B horizons, was classified into Para-Kuroboku soils. In clay mineral compositions of Site 1 and 4, Al-vermiculite was dominant, and chlorite and illite were also observed. These crystalline clay minerals were deduced to be derived from aeolian mica that was contained in a coast deposit distributed along coasts of this region, and might be mixed with volcanic ash soils. Surface soils originated from young volcanic ash soils might be eroded and parent materials of old deposits in deeper horizons might form present Para-Kuroboku soil of Site 1 which showed high silicate aluminum ratio. Soil in each Site was classified into Typic Para-Kuroboku soil for Site 1, Typic Yellowish-Brown Forest soil for Site 2, Acidic-Brown Forest soil for Site 3, Typic Kuroboku soil for Site 4 and Site 5."